1. Editing- You need to hire a copy editor. This will probably cost you around $1200 plus. Put it in your budget and don't think a friend is the better option. A good self published book needs to be just as clean and sharp as a book published by a New York Publishing House. I see way too many errors in self published books and it makes me put them right down.
For example, I just worked with someone on a developmental edit (something I totally recommend). They even had a professional artist do the cover, but when it came time for the edits, they didn't want to spend the money so a friend said they'd do it for free. When this book appeared on Amazon I was so excited. I ordered a copy immediately and was thrilled that I had worked on the book. I was shocked when I opened it. Within the first 10 pages there were 3 errors! Obvious, huge errors that involved both spelling and grammar. I was so upset. Not just because I'd put my name out there recommending the book (the story is fab), but because errors are just not acceptable. One maybe in a whole book, but 3 within the first few pages. Ugh! if you want a professional book, pay for the edit! and when that's done, read through it one more time.
2. Cover Art- You need to hire a professional cover artist. Covers are what cause a reader to pick up your book or click on the Amazon link. Do not try to do it yourself. Those types of covers do stand out, but in the wrong way. I will completely skip over and avoid those books. They are so obvious and stock art only gives your cover one dimension.
You need to be picky too, On my second book I used Createspace to design the cover. It cost me $500, so you'd think it would have been amazing. Nope, it was horrible. They even make me pay for any changes. This was my first experience, so I didn't know what to do. On my next book, a friend sent me the links to several professional cover artists. I was able to look at their online portfolio's and see their talent for myself. I had a wonderful experience and the cover was amazing. I even rehired the artist to redo the cover of my Createspace book. It is 100% better. Let me show you- the first cover is the original and the second is from the cover artist. Remember, it costs to publish a book, don't let anyone tell you different.